Molecular hybridization strategy for tuning bioactive peptide function

The physicochemical and structural properties of antimicrobial peptides (AMPs) determine their mechanism of action and biological function. However, the development of AMPs as therapeutic drugs has been traditionally limited by their toxicity for human cells. Tuning the physicochemical properties of such molecules may abolish toxicity and yield synthetic molecules displaying optimal safety profiles and enhanced antimicrobial activity. Here, natural peptides were modified to improve their activity by the hybridization of sequences from two different active peptide sequences. Hybrid AMPs (hAMPs) were generated by combining the amphipathic faces of the highly toxic peptide VmCT1, derived from scorpion venom, with parts of four other naturally occurring peptides having high antimicrobial activity and low toxicity against human cells. This strategy led to the design of seven synthetic bioactive variants, all of which preserved their structure and presented increased antimicrobial activity (3.1–128 μmol L−1). Five of the peptides (three being hAMPs) presented high antiplasmodial at 0.8 μmol L−1, and virtually no undesired toxic effects against red blood cells. In sum, we demonstrate that peptide hybridization is an effective strategy for redirecting biological activity to generate novel bioactive molecules with desired properties.

MHC value was considered the concentration that there were approximately 0% of hemolytic activity.
Table S4.Resistance to degradation studies.Peptides were exposed to fetal bovine serum enzymes for 6 h and the remaining peptide was calculated based on liquid chromatography coupled to mass spectrometry experiments.

Figure S1 .
Figure S1.Histopathological analysis of the murine skin tissue after the scarification procedure.The mice were shaved, and a scarification was performed with the tip of a needle on their back.Next, mice were (a) infected with A. baumannii or (b) left untreated.Samples were treated with either (c) VmCT1 (8 mol L -1 ), (d) TV (16 mol L -1 ), and (e) Polymyxin B (20 mol L -1 ).One representative image for each condition is shown in the figure.

Figure S2 .
Figure S2.A) Chromatogram, B) Mass spectrum and C) Mass Scan of VmCT1 from 13.270 to 13.821 min at the conditions specified in the Experimental Section.

Figure S3 .
Figure S3.A) Chromatogram, B) Mass spectrum and C) Mass Scan of Anoplin from 15.911 min at the conditions specified in the Experimental Section.

Figure S4 .
Figure S4.A) Chromatogram, B) Mass spectrum and C) Mass Scan of AV from 18.600 min at the conditions specified in the Experimental Section.

Figure S5 .
Figure S5.A) Chromatogram, B) Mass spectrum and C) Mass Scan of Protonectin from 19.860 min at the conditions specified in the Experimental Section.

Figure S6 .
Figure S6.A) Chromatogram, B) Mass spectrum and C) Mass Scan of PV from 13.429 to 13.980 min at the conditions specified in the Experimental Section.

Figure S7 .
Figure S7.A) Chromatogram, B) Mass spectrum and C) Mass Scan of PV from 11.427 to 12.001 min at the conditions specified in the Experimental Section.

Figure S8 .
Figure S8.A) Chromatogram, B) Mass spectrum and C) Mass Scan of Decoralin at the conditions specified in the Experimental Section.

Figure S9 .
Figure S9.A) Chromatogram, B) Mass spectrum and C) Mass Scan of DV from 10.636 to 11.570 min at the conditions specified in the Experimental Section.

Figure S10 .
Figure S10.A) Chromatogram, B) Mass spectrum and C) Mass Scan of VD from 11.043 to 11.785 min at the conditions specified in the Experimental Section.

Figure S11 .
Figure S11.A) Chromatogram, B) Mass spectrum and C) Mass Scan of Temporin A from 13.917 to 14.851 min at the conditions specified in the Experimental Section.

Figure S12 .
Figure S12.A) Chromatogram, B) Mass spectrum and C) Mass Scan of VT from 13.605 to 14.300 min at the conditions specified in the Experimental Section.

Figure S13 .
Figure S13.A) Chromatogram, B) Mass spectrum and C) Mass Scan of TV from 13.438 to 14.156 min at the conditions specified in the Experimental Section.

Table S1 .
Biological activity and structural characterization of the peptides.

Table S2 .
Antimicrobial activity of the peptides against several ESKAPE pathogens.

Table S3 .
Helical fraction of the wild-type and analogs in seven different media calculated by using Lifson-Roig helix-coil theory.77